<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    *{
      margin: 0;
      padding: 0;
    }
  .box{
      width: 200px;
      height: 100px;
      padding: 20px;
      border: 5px solid black;
      margin: 20px;
    }
    .border-box{
      background-color: lightblue;
      box-sizing: border-box;
    }
    .content-box{
      background-color: red;
      box-sizing: content-box;
    }
  </style>
</head>
<body>
  <div class="box border-box" >Border with border-box</div>
  <div class="box content-box">Border with border-content</div>
</body>
</html>